Dialkyl 1-acryloyloxy-2-alkenyl-1-phosphonates and dialkyl 1-methacryloxy-2-alkenyl-1-phosphonates

ABSTRACT

Dialkyl 1-acryloyloxy-2-alkenyl-1-phosphonates and dialkyl 1methacryloyloxy-2-alkenyl-1-phosphonates are prepared by reacting a dialkyl 1-hydroxy-2-alkenyl-1-phosphonate with acryloyl- or methacryloyl chloride in the presence of a base, using preferably an inert organic solvent. The dialkyl 1-acryloyloxy-2-alkenyl-1phosphonates and the dialkyl 1-methacryloyloxy-2-alkenyl-1phosphonates produced are novel compounds. They are useful as flame retardant and cross-linking comonomers in the preparation of self-extinguishing and/or flame retardant polymers. They also can be homopolymerized to give novel phosphorus containing, selfextinguishing polymers.

United States Patent Iliopulos et al.

[ 1 Apr. 22, 1975 DIALKYL l-ACRYLOYLOXY-Z-ALKENYL-l- PHOSPHONATES AND DIALKYL v l-METHACRYLOXY-2-ALKENYL-1- PHOSPHONATES [76] Inventors: Miltiadis I. lliopulos, 32

Willowbrook Acres, Parkersburg. W. Va. 26101; Werner K. E. Ege, l 1 London Ring, 67 Ludwigshafen am Rhine, Germany [22] Filed: Aug. 31, 1971 [21] App]. No.: 176,712

[52] [1.5. CI. 260/952; 260/2 P; 260/970;

[51] Int. Cl C07f 9/40; c08f 3/00 [58] Field of Search 260/952 [56] References Cited UNITED STATES PATENTS 3.030347 4/1962 O'Brien et al. 260/952 X OTHER PUBLICATIONS lliopulos, Beilrage zur chemie phosphororganischen verhindungen" (Thesis), M-l lliopulos, June 3, 1970.

Primary E.\'aminer-Anton H. Sutto Attorney, Agent, or Firm-Neal .lv Mosely ABSTRACT Dialkyl l-acryloyloxy-Z-alkenyl-l-phosphonates and dialkyl l-methacryloyloxy-2-alkenyll -phosphonates are prepared by reacting a dialkyl 1-hydroxy-2- alkenyl-l-phosphonate with acryloylor methacryloyl chloride in the presence of a base, using preferably an inert organic solvent. The dialkyl l-acryloyloxy-2- alkenyll -phosphonates and the dialkyl 1- methacryloyloxy-2-alkenyl-l'phosphonates produced are novel compounds. They are useful as flame retardam and cross-linking comonomers in the preparation of self-extinguishing and/or flame retardant polymers. They also can be homopolymerized to give novel phosphorus containing, self-extinguishing polymers.

8 Claims, N0 Drawings DIALKYL lI-ACRYLOYLOXY-Z-ALKENYL-l- PHOSPHONATES AND DIALKYL I-MIETHACRYLOXY-2-ALKENYL-l- PHOSPHONATES BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION This invention relates to novel phosphorus containing organic unsaturated compounds and to a process for their preparation. In particular, this invention is concerned with the preparation of novel dialkyl lacryloyloxy-Z-alkenyl-Lphosphonates and the dialkyl l-methacryIoyloxy-Z-alkenyl-l-phosphonates which are useful intermediates for the preparation of homoand copolymers. These compounds act also as weak cross'linking agents because they possess two olefinic linkages of different reactivities.

2. DESCRIPTION OF THE PRIOR ART In the course of our investigations of novel vinyl type unsaturated organophosphorus monomers which were carried out during the years I960 968 at the Institute of Organic Chemistry and Organic Chemical Technology of the University of Stuttgart (formerly Institute of Technology of Stuttgart) some novel derivatives of the series of the dialkyl l-acryloyloxy-alkyl- I phosphonates and the dialkyl l-methacryloyloxyalkyl-l-phosphonates have been prepared and tested as flame retardant comonomers. l. werner K. E. Ege, Darstellung polymerisationsfahiger Phosphonsaeurediester. Versuche zur Herstellung eines flammfesten Polymethacrylats durch Copolymerisation dieser Ester mit Methacrylsaeuremethylester, Dissertation, pages 75, Technische Hochschule Stuttgart, 1964; 2. Miltiadis loannu lliopulos, Beritraege zur Chemie phosphororganischer Verbindungen, Habilitationsschrift, pages 368, University of Stuttgart, published end of August, 1970 in the Federal Republic of Germany These compounds are named as dialkyl phosphonoalkyl acrylutes and methacrylates in the U.S. Pat. Nos. 2.934.555 and 3,030,347.

These compounds were obtained by the reaction of dialkyl l-hydroxyalkyl phosphonate with an a,B-unsaturated acyl chloride in the presence of an acid acceptor. However, at that time a number of publications appeared dealing with the preparation of polymerization of some members of the above mentioned classes. 3. J. L. OBrien and C. A. Lane, U.S. Pat. No. 2,934,555, I960; Chemical Abstracts 54, 18,357 c 1960; 4. CG. Overberger and E. L. Sarlo, Journal of Organic Chemistry, 26, 4711, 1961; 5. .I. L. OBrien and C. A. Lane, U.S. Pat. No. 3,030,347, 1962; Chemical Abstracts 57,2431 i, 1962; 6. A. N. Pudovik, E. I. Kashevarova and Yu. P. Rudnef, Dokl. Akad, Nauk, SSSR 140, 841, 1961; Chemical Abstracts 56, 3,506, 1962).

Out attention was then devoted to the synthesis, characterization and polymerization of the novel dialkyl lacryloyloxy-2-alkenyl-l-phosphonates and the dialkyl l-methacryloyloxy-2-alkenyl-l -phosphonates described herein in view of the fact that our studies concerning the reaction mechanism of the addition of the dialkyl hydrogen phosphites to a,B-unsaturated aldehydes in the presence of catalytic amounts of a base, had enabled us to improve considerably the yields and purity of the dialkyl l-hydroxy-2alkenyl-lphosphonates which are used as starting materials for the preparation of the composition of matter described in this invention. (Reference No. 2).

'phosphonates the dialkyl l-hydroxy-2-alkenyl-l-phosphonates were for the first time described by A. E. Arbuzov, by A. N. Pudovik and Yu. P. Kitaev and by E. K. Fields.(7. A. E. Arbuzov, Doklady Akad, Nauk SSSR, 73, 499-502, 1950; 8. A.N. Pudovik and Yu. P. Kitaev, Zhurnal Obschei Khimii, 22, 467, 1952; Chemical Abstracts 47; 2,687, 1953; 9. A. N. Pudovik, Zhurnal Obschei Khimii 22, I371, 1952; Chemical Absracts 47; 4,837, I953; 10. E. K. Fields, U.S. Pat. No. 2,579,810 (1951); Chemical Abstracts 46; 6,140, 1952).

Our interest in the preparation of the herein described novel dialkyl l-acryloyloxy-2-alkenyl-land dialkyl l-methacryloyloxy-2- alkenyl-l-phosphonates was aroused because these compounds possess two olefinic linkages of different reactivities, and hence on homoor copolymerization are capable of yielding cross-linked polymers which are desirable in the production of flame retardant and/or self-extinguishing polymers for certain industrial applications.

SUMMARY OF THE INVENTION This invention relates to novel unsaturated phosphorus containing organic compounds and to a process for their preparation. The compounds of this invention are presented by the following general structural formula IOl u CH C C-O-CH P\ I I 2 03 R 0- wherein: R is a member of the class consiting of hydrogen and methyl. R is a member of the class consisting of hydrogen and alkyl groups having one to four carbon atoms, e.g., CH C H iso-C I-I etc., R and R each is independently selected from the group consiting of hydrogen, alkyl of l to 4 carbon atoms or phenyl; they may be the same or different. R represents an alkyl of l to 6 carbon atoms, preferably of l to 4 carbon atoms which may be or may not be substituted with halogens, e.g., Cl, Br, F or I.

In accordance with this invention the novel compounds of the invention are prepared by the addition of a dialkyl hydrogen phosphite of formula (2) to an a,B-unsaturated aldehyde of formula (3) 5 R :0 z c -GHO in the presence of a catalytic amount of a base to form the dialkyl l-hydroxy-2-alkenyl-l-phosphonate of formula (4) R the unreacted dialkyl l-hydroxy-2-alkenyl-l C G. CH(OH) P(ORS) phosphonate cannot be removed by distillation because l 2 it forms an azeotrope with the dialkyl l-acryloyloxy- R R and/or l-methacryloyloxy-2-alkenyl-1-phosphonate, it

may be desirable to employ an excess of the a,B-unsatfollowed by reaction of the latter intermediate with acurated acyl chloride and of the base. In an inert organic ryloylor methacryloyl chloride in the presence ofahysolvent is employed in the reaction of the dialkyl l drogen chloride acceptor such as pyridine. triethylamhydroxy-Z-alkenyl-l-phosphonate with the a,B-unsatume, d1methylan1lme, diethylaniline or sodium carbon- 10 rated acyl chloride it is advantageous to use a solvent "3 the i the itue ts in which the amine hydrochloride and the acyltrialk- R and R as defined i formula ylammonium chloride are insoluble so that these by- The synthetic procedure is illustrated by the followproducts can b removed by filtration. mg equatlons and The solvent may be removed by distillation, evapora- 0125 0 R5 G c/ 1 Base 5 (A) 4 H-P-9O ----9 R 2 l 5 R 2 101 0 IO\ U 4 5 Base (a) OH mm no-c ra-flon T CH g: C-O-GH-P(OR R G-R R 0. (5) g g I ln contacting the reaction according to the equation (A) in the presence of a tert. organic base for the preparation of the intermediate dialkyl l-hydroxy-Z- alkenyl-l-phosphonates the sequence of the charge of the reactants as described by E. K. Fields (reference No. can not be followed because in the most cases the tert. organic base catalyzes strongly the polymerization of the afi-unsaturated aldehyde, even in the presence of stabilizers and at low temperatures. (1 1. N. G. Koralnik The Chemistry of Acrolein and its Polymers, Sb. Nauchn. Issled. Rabot. Khim. in Khim. TekhnoL, Vysokomolek. Soedin, Tashkentsk. Tekstiln Inst. 1964, 1, 5-83; Chemical Abstracts 63, 17,882 d, 1965). For example, the polymerization of acrolein in the presence of phosphorus compounds and tert. organic bases has been recently investigated. (12. Deutsche Goldund Silberscheideanstalt A. G. (DEGUSSA), Dutch Pat. No. App. P 6,411,783 1965; Chemical Abstracts63, 12,299 h, 1965).

However, the results of our investigations concerning the reaction mechanism of the addition of the dialkyl hydrogen phosphites to certain classes of carbonyl compounds (reference No. 2) has enabled us to elaborate the optimal reaction conditions of the reaction illustrated in equation (A) and therefore to obtain the intermediate dialkyl l-hydroxy-Z-alkenyll phosphonates in high yield and purity. For example, in many instances the crude dialkyl l-hydroxy-2- propenyl-l-phosphonate can be reacted with the a,,B-unsaturated acyl chloride without previous purification. in contacting the reaction according to the equation (B), generally, the reactants are employed in equimolar equantities. However, in view of the fact that in some instances the conversion is not complete and tion or by any other suitable method. The organic solvents utilized in this invention include low molecular weight aliphatic or alicyclic ethers such as diethyl ether, di-isopropyl ether, dibutyl ether, tetrahydrofurane or p-dioxane and aromatic hydrocarbons such as benzene, toluene, xylene and the like.

The phosphorus containing monomers described in this invention can be polymerized alone or can be copolymerized with one or more other vinylidene compounds to form copolymers. Examples of such mono mers which can be copolymerized with the dialkyl 1- acryloyloxy-Z-alkenyl-l-phosphonates or the dialkyl 1-methacry1oyloxy-2-a1kenyl- 1 -phosphonates include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, lauryl acrylate, lauryl methacrylate, butyl acrylate, styrene, acrylonitrile, vinyl acetate and the like.

the processes of polymerization which may be em ployed in the preparation of either homopolymers or copolymers include polymerization in bulk, in solution, in emulsion, or in suspension. These methods of polymerization are well known in the art.

the homopolymers derived from the novel organophosphorus compounds described in this invention and certain of their copolymers are particularly useful as flame resistant and/or self-extinguishing novel polymeric compositions. Other applications for the polymers and copolymers are, for example, in coatings, textile and leather finishes.

The following examples are presented to illustrate the novel compounds of this invention and their preparation and utility. It is intended that the examples be considered as illustrative rather than limiting on the invention disclosed as claimed herein.

EXAMPLE 1 lnto a 500 ml three necked flask equipped with a refluxcondenser, a mechanical stirrer, a thermometer and a dropping funnel was charged 22.0 grams (0.2 mole) of dimethyl hydrogen phosphite and l 1.2 grams (0.2 mole) of freshly distilled acrolein. The resulting mixture was stabilized with 0.75 grams of phydroquinone. Through the dropping funnel and over a period of 30 minutes while stirring and cooling there was added dropwise 1.7 ml of a saturated solution of sodium methoxide in absolute methanol. Due to the exotherm the temperature of the reaction mixture rose from -5 to 25C. Thereafter the reaction mixture was stirred at 30C for 30 minutes and the free base neutralized with an equivalent amount of glacial acetic acid. To the crude dimethyl l-hydroxyprepen2-yl-1 -phosphonate were then added 21.20 grams (0.2 mole) of anhydrous powdered sodium carbonate and the resulting inhomogeneous mixture was diluted with 200 ml of anhydrous diethyl ether. Thereafter 20.91 grams (0.2 mole) of methacryloyl chloride, stabilized with 0.01 gram of copper(l) chloride were added dropwise at 30 to 34C over a period of 50 minutes. Stirring was continued for 24 hours at room temperature and the temperature finally raised to 37C. for 1 hour. The reaction mixture was filtered and the ether removed under reduced pressure in the presence of 2.0 grams of N,N'-di- 2( l.4-naphthoquinonyl)-p-phenylenediamine.

Distillation of the residue yielded 23.4 grams (50 percent yield) of dimethyl 1-methacryloyloxy-propen-Z-yll-phosphonate of the formula G 4 ll a r pa o-meapma ca CH u 5 2 boiling at 93-96C/0.l mm Hg; n 1.4599. Analysis: Calcd. for C H, O P C 46.15%, H 6.46%, P

I 13.23%. Found: C 46.47%; H 6.77%, P 13.12% (flame photometry) ln a second run the intermediate dimethyl l-hydroxypropen-Z-yll-phosphonate was subjected to high vacuum fractional distillation to give 28.6 grams (86 percent yield) of an analytically pure sample of this compound boiling at l00C/0.01 mm Hg. Analysis: Calcd. for C T-[ 032 C 36.15%, H 6.68%. Found C 36.01%, H 6.99%

5 EXAMPLE 2 A mixture of 55.24 grams (0.4 mole) of freshly distilled diethyl hydrogen phosphite and 4.04 grams (0.04 mole) of triethylamine containing 0.06 grams of phydroquinone as inhibitor was placed in the apparatus described in example 1. The mixture was cooled to 0C by external cooling. While maintaining the temperature between 4 and 8C. by cooling, 22.42 grams (0.4 mole).of distilled acrolein, stabilized with 0.05 gram of p-hydroquinone was added'dropwisewith vigorously stirring. After completion of the addition the temperature of the stirred reaction mixture was risen to 80C. within 1 hour, with the aid of an electrically heated oil bath.

Upon removal of the triethylamine under reduced pressure, the crude oily product obtained in a theoretical yield was distilled under nitrogen to give 62.2 grams percent yield) of diethyl l-hydroxy-propen-2-yl-lphosphonate of the formula t (G2H50)2P-CH(OH)-CH 01:1

The compound was an odorless and colorless oil boiling at 122-1l3C/0.024 mm Hg. analysis: Calcd. for C H O P: C 43.30%, H.7.78%, P

15.95%. Found: C 43.40%, H 7.77%, P 15,93% (flame photometry).

EXAMPLE 3 Using the glass apparatus described in Example 1, a solution of 9.05 grams (0.1 mole) of acryloyl chloride in 20 ml of anhydrous diethyl ether was added dropwise to a vigorously stirred solution of 8.4 grams (0.05 mole) of dimethyl 1-hydroxy-propen-2-yl-phosphonate prepared in Example 1 and 10.1 grams (0.1 mole) of triethylamine in ml of anhydrous tetrahydrofurance containing 0.06 grams of copper(l)-chloride and 0.0] gram of N,N'-di-2(l.4-naphthoquinonyl)-pphenylenediamine, both acting as polymerization inhibitors. During the addition of the acryloyl chloride the temperature of the reaction mixture was held below 15C by external cooling.

After removal of the diethyl ether through evaporation, the reaction mixture was heated with stirring at 60C. for approximately 1 hour. Thereafter the reaction mixture was cooled to 0C and the insoluble byproducts consisting of the triethylamine hydrochloride and of the adduct of the acryloyl chloride to triethylamine was filtered off. The tetrahydrofurance was then removed under reduced pressure and the obtained crude product redissolved in ml of diethyl ether in order to precipitate the small quantity of the above mentioned salts which was soluble in the tetrahydrofuraneproduct mixture.

After evaporation of the ether. the crude product ob tained in an almost quantitative yield was subjected to high vacuum fractional distillation under nitrogen yielding 6.8 grams (62 percent yield) of analytically pure dimethyl 1-acryloyloxy-propen-2-yl-1- phosphonate of the formula The compound is a colorless liquid boiling at 95C/0.05 mm Hg; n,, 1.4605.

Analysis: Calcd. for C H O P: C 43.64%, H 5.96%, P 14.07%. Found: C 43.40%, H 6.06%, P 14.30% (flame photometry).

EXAMPLE 4 If in Example 3, methacryloyl chloride (10.54 grams) was employed in place of acryloyl chloride, there was obtained, upon completion of the steps therein described, dimethyl 1-methacryloyloxy-propen-2-y1- l phosphonate of the formula 7 8 I01 gave diethyl 1-methacryloyloxy-propen-Z-yl-1 -phosq '11 phonate of the fomula (CH O) P-CH-O-C-C =CH CH 5 f 181 ll P-cH-o-o-c CH CH 2 i l 2 CH CH u 5 in a 71% yield, as a colorless liquid boiling at 50C.0.06 CH mm Hg; n 1,4601. 2

Analysis: Calcd. for C H O P: C 46.15%, H 6.46% P 13 23% F d; C 46.39% H 658, P 13 26% (flame in a 75 percent yield. the colorless liquid compound photometry). distilled at 8586C/0.025 mm Hg; n 1,4530.

Infrared analysis confirmed the structure of the com- 15 Analysis: Calcdfor |1 19 5 C H 730%. P pound. 11.81%. Found: C 50.48%. H 7.65%. P 12.28%

' J EXAMPLE 5 EXAMPLES 7-11 Following the procedure f E m l 3 d using th A series of additional experiments were carried out same molar proportions of th reactants, di th l 1. 20 which are tabulated below in Table 1. These examples acryloyloxy-propen-Z-yl-1-phosphonate was prepared illustrate the preparation of a variety of members of in a 76 percent yield from 9.7 grams diethyl 1- this novel class of organophosphorus monomers and hydroxypropen-2-yl-l-phosphonate and 9.05 gra f demostrate the variation of substituents on each of the acryloyl chloride. Triethylamine was used as acid acreactants.

OI TABLE I fig R R R R R %yield 7 H H I H H 0 11,91 a7 8 H CH H H 1360 11 I 85 CH 68 9 ()H CH 0 1-1 H- 5 C H 60 1O 0H 0 11 H (3 H 2 5 l1 CH H C H H 0 H '59 ceptor. The diethyl 1-acryloyloxy-propen-2-yl-l- EXAMPLE 12 Phosphonate of the formula 50 Homopolymer of dimethyl l-acryloyloxy-propen-2- yl- 1 -phosphonate.

Q o Twenty-five grams of freshly distilled dimethyl l- 4 ll acryloyloxy-propen-Z-yl-l-phosphonate monomer pre- (G H O) P-QH-O-C-CH =CH pared in Example 3 and 0.25 gram of benzoyl peroxide CH were mixed and placed in small glass vial immersed-1n u an oil bath at C. After 8 hours the vial was removed CH and its content found to consist of a clear, hard. selfextinguishing homopolymer.

distilled at 90C/0.03 mm Hg; nf" 1.4532. 60 EXAMPLE Analysis: Calcd. for C H O P: C 48.39%, H 6.90%. P Homopolymer of dimethyl l-methacryloyloxy- 12.48%. Found: C 48.48%. H 7.18%, P 12.52% (flame propen-2-yl-1-phosphonate.

photometry) Following the procedure of Example 12 a homopolymer was prepared from 25 grams of dimethyl 1- EXAMPLE 6 methacryloyloxy-propen-Z-yl-l-phosphonate and 0.25

In 11 S r manner, reaction of m t y y Chloj gram of benzoyl peroxide. There was obtained a clear, ride with diethyl l-hydroxy-propen-2-yl-1-phosphonate h rd, lfti i hi pl tic,

EXAMPLE 14 Copolymer of diethyl l-methacryloyloxy-propen-2- yl-lphosphonate and methyl methacrylate.

Forty grams of diethyl l-methacryloylxy-propen-2- yll-phosphonate monomer, prepared in Example 6, 60,0 grams of methyl methacrylate and 1.0 gram of benzoyl peroxide were charged in a beaker and placed in an electric over. The reaction mixture was heated at 60C. for 4 hours to produce a hard, transparent, amorphous polymer with a phosphorus content of 4.60 per- I cent (Theory 4.68 percent).

Upon testing for flammability by holding a specimen in a flame of a Bunsen burner until ignited the polymer was found to be self-extinguishing.

EXAMPLE l5 Copolymer of dimethyl 1-acryloyloxy-propen-2-yl'lphosphonate and methyl methacrylate.

polymer having a phosphorus content of 2.74 percent. (Theory requires 2.79 percent).

The degree of flame resistance and the physical properties of the polymer can be altered extensively by varying the compostion of the copolymer.

We claim: 1. A compound having the general formula I /OH OH G -C-O-CH-P I 2 OH R C-R II C R R wherein R is a member of the class consisting of hydrogen and methyl, R is a member of the class consisting of hydrogen and an alkyl group having 1 to 4 carbon atoms, R and R are independently selected from the class consisting of hydrogen, of an alkyl group of l to 4 carbon atoms and phenyl, and R is an alkyl or haloalkyl of l to 6 carbon atoms, preferably 1 to 4 carbon atoms.

2. A compound as defined in claim 1 in which R, R R and R are hydrogen, and R is methyl.

3. A compound as defined in claim 1 in which R, R R and R are hydrogen, and R is ethyl.

4. A compound as defined in claim 1 in which R R and R are hydrogen, and R and R are methyl.

5. A compound as defined in claim 1 in which R R and R are hydrogen, R is methyl and R is ethyl.

6. A compound as defined in claim 1 in which R, R, R and R are hydrogen and R is chloroethyl.

7. a compound as defined in claim 1 in which R R, R are hydrogen, R and R is chloroethyl.

8. A compound as defined in claim 1 in which R, R

and R are hydrogen, R is methyl and R is isopropyl. 

1. A compound having the general formula
 1. A COMPOUND HAVING THE GENERAL FORMULA
 2. A compound as defined in claim 1 in which R1, R2, R3 and R4 are hydrogen, and R5 is methyl.
 3. A compound as defined in claim 1 in which R1, R2, R3 and R4 are hydrogen, and R5 is ethyl.
 4. A compound as defined in claim 1 in which R2, R3 and R4 are hydrogen, and R1 and R5 are methyl.
 5. A compound as defined in claim 1 in which R2, R3 and R4 are hydrogen, R1 is methyl and R5 is ethyl.
 6. A compound as defined in claim 1 in which R1, R2, R3 and R4 are hydrogen and R5 is chloroeThyl.
 7. a compound as defined in claim 1 in which R2, R3, R4 are hydrogen, R1 and R5 is chloroethyl. 